Titanium base alloys



United States Patent TITANIUM BASE ALLOYS Robert 1. Jatfee, Worthington,and Horace R. Ogden and Daniel J. Maykuth, Columbus, Ohio, assignors, bymesne assignments, to Crucible Steel Company of JAmerica, Flemington,N.J., a corporation of New ersey No Drawing. Application July 9,1956Serial No. 596,459

1 Claim. (Cl. 75-'175.5)

This invention pertains to improvements in titanium base alloys, andprovides a series of alloys of high strength and ductility, and, as tocertain analyses, also of high contamination resistance and highstrength at elevated temperatures, and containing as essentialconstituents ti- ,tanium and tin, together with one or more additionalmetals selected from the groups comprising alpha promoters, betapromoters and compound formers as enumerated below.

This application is a continuation-in-part of our applications SerialNos. 285,076, filed April 29, 1952, now US. Letters Patent No.2,669,513, dated February 16, 1954; 294,262 and 294,263, both filed June18, 1952, and

- both now abandoned; 344,686, filed March 25, 1953, now

abandoned; and 396,756, filed December 7, 1953, now Patent No.2,797,996, granted July 2, 1957.

The tin content may be present over a broad range of about 0.5 to 23%,with a preferred lower limit of about 2.5%, as adjudged from thestandpoint of good room temperature mechanical properties, and apreferred lower limit of about as regards the imparting of highcontamination resistance at elevated temperatures. To the titanium-tinalloy aforesaid, there may advantageously be added up to about 18% inaggregate of one or more of the alpha promoters, up to about 50% inaggregate of one or more of certain of the beta promoters, and up toabout 2 or 3% in aggregate of the compound formers, all as set forthmore in detail hereinafter. For further enhancing the mechanicalproperties, the alloys of the invention may contain controlled amountsof the interstitials, carbon, oxygen and nitrogen. For certain analyses,as set forth below, carbon may be present up to about 1%, oxygen up toabout 0.5% and bined with adequate ductility for both hot and coldforming operations, i.e., forging, rolling, drawing, extruding, etc. Fortin contents up to about 16%, they may likewise, in general, be weldedwithout appreciable loss of ductility in the welded as compared to thenonwelded portions. This is particularly true as regards those alloyshaving an all-alpha microstructure, and also as to certain of thosehaving a beta-containing microstructure, as explained more in detailbelow.

For imparting a high degree of contamination resrstance, i.e.,resistance against penetration by atmospheric gases, particularly oxygenand nitrogen, at elevated temperatures up to about 1100 C., the alloysshould contain upwards of about 5% tin, although lesser amounts down toabout 2% tin are materially beneficial in this respect. Tin alloyed withtitanium base metal appears to be unique in imparting this contaminationresistance, and its effect is quite critical with respect to the degreeof contamination resistance imparted. commencing at a minimum of about5% tin.

These contamination resistant alloys are also characterized by freescaling properties resulting from explosure to elevated temperatures upto about 1100 C. and to atmospheric, oxidizing, or alternately oxidizingandreducing conditions. That is to say, the scale formed is easilybrushed ofi or flakes off during hot forming operations, such as forgingor rolling.

As is known, the metal titanium in the pure state, is capable ofexisting in either of two allotropic forms. Below a temperature of about885 C. or 1625 F., it assumes a close-packed hexagonal structure knownas the alpha phase, while at this temperature and above it assumes abody-centered cubic structure known as the beta phase.

Certain substitutional alloying additions to the titanium base metal,among which may be mentioned tin, antimony, indium, silver, bismuth,lead, cadmium, zinc, and thallium as well as the interstitials carbon,oxygen, and nitrogen may be termed alpha stabilizers or alphapromoters.The term alpha stabilizer includes those elements which raise thetransformation range sharply, such as oxygen and nitrogen. Also alphastabilizers include elements such as carbon, which have a relativelysmall solubility in alpha titanium, but which raise the transformationtemperature for that amount which is in solution. Alpha stabilizers alsoinclude those elements such as tin, antimony, indium, and silver whichhave relatively large solubilities, of about the same magnitude, in boththe alpha and beta phases and which have little effect on thetransformationtemperature range, neither raising nor lowering itmarkedly. A common characteristic of the alpha stabilizers, as we areconsidering them here, is that little or no hardening occurs in thethermal processing. The resulting alloys are, at room temperature,always all alpha in structure regardless of the heat treatment,including quenching or aging. Actually little is known concerning thespecific eifects of bismuth, lead, cadmium, zinc, and thallium on thetransformation range. These alloying elements produce alloys which fitthe criteria given, namely, that they form all-alpha alloys, which donot retain any substantial content of beta phase nor harden appreciablyon quenching from the beta field. Hence these elements appear properlyclassified as alpha promoters, and will be so treated in thisapplication.

Other substitutional alloying elements, when added in progressivelyincreasing quantities, stabilize the beta phase at progressively lowertemperatures, until a mixed alphabeta or stable all-beta microstructureis obtained at normal or atmospheric temperatures, or the beta phaseundergoes a eutectoid reaction, depending on the character and amount ofthe beta stabilizers added as discussed below.

Speaking in broadest terms, the beta stabilizers are Mo, V, Cb, Ta, Zr,Mn,'Cr, Fe, W, Ni, Co and Cu.

3 Silicon and beryllium may also be considered as beta stabilizingelements, but their solubilities in titanium are relatively so slightand the tendency of the beta phase stabilized by these elements todecompose into eutectoid products so great, that it is equally proper toconsider them as compound-forming elements. Within this broad category,however, only certain of the elements mentioned are suitable forproducing mixed-phase, alphabeta alloys, or all-beta alloys. -These arethe elements which have beta-isomorphous diagrams, or which havebeta-eutectoid diagrams such that the decomposition of the beta phaseinto eutectoid is so sluggish that the alloys behave like those in abeta-isomorphous system. The beta stabilizing elements of this type areMo, V, Cb, Ta, Mn,"Fe and Cr. Tungsten is a borderline element asbetween the sluggishly decomposing and rapidly decomposing types andhence may be classified either way. Within this limited group only Mo,V, Cb. and Ta are beta-isomorphous. They form the most thermally stablebeta-containing alloys, as a result of their beta-isomorphism.

Zirconium is a beta promoter or stabilizer in the sense that the lowesttemperature at which alloys thereof with titanium are entirely beta,becomes progressively lower with increasing amounts of zirconium, untila composition is reached at which this so-called beta transustemperature starts to increase again with further additions ofzirconium. While zirconium thus lowers the transformation temperature oftitanium, the alloys eventually revert to the alpha phase at lowertemperatures unless other beta-promoters are present. Zirconium isisomorphous with titanium both in the alpha and beta fields. As aresult, it is proper to consider zirconium together with vanadium,molybdenum, columbium and tantalum as all being beta-isomorphous withtitanium.

The use of copper alone as an alloying addition to titanium, does notfit into the above-mentioned grouping of beta-isomorphous and sluggishlydecomposing eutectoil beta promoters, because the beta phase stabilizedby copper always decomposes rather rapidly into proeutectoid andeutectoid products, and the same is generally true with respect tocobalt, nickel, silicon and beryllium, above listed under the broadcategory of beta stabilizers. Copper, however, is a useful addition whenpresent as a minor alloying element, for example,

up to a few percent, in alloys containing larger amounts of otherbeta-stabilizing elements, within the narrow group of elements lastmentioned above since, in these low concentrations and in the presenceof such other beta-stabilizing elements, the tendency of the beta phasestabilized in part by copper to decompose into eutectoid products isminimized or entirely eliminated.

The tolerance of the ductile TiSn base alloys of the invention withrespect to additions of the various beta promoters above mentioned,varies considerably for the individual elements of the group, beinggreatest with respect to those which form beta-isomorphous systems withtitanium, and least for those which decompose most readily intoeutectoid decomposition products. Thus, the TiSn base alloys may bestrengthened without undue embrittlement by additions of up to about 50%in aggregate of elements composing the. beta-isomorphous group, viz.,molybdenum, vanadium, columbium, tantalum and zirconium, since theseelements are soluble in all proportions in beta titanium. Of thesluggishly decomposing elements, the base alloy will tolerate additionsof up to about 20% of either or both chromium and tungsten, up to about10% manganese, and up to about 7% iron. Copper may be added up to about7%. Metal of the group cobalt and nickel 'may be added up to a total ofabout For additions of all of the abovementioned beta-promoters, thelower effective limit is about 0.5% and preferably about 1%.

The tolerance of the ductile TiSn base alloys for the alpha promotersdepends on the amount of tin present, the less tin present the greaterthe amount of alpha-promoters that can be added and vice versa. Antimonymay be added to a maximum content of 18%. The proportioning of antimonycontent in relation to the tin content is given below. Indium may beadded up to a maximum content of 15 Silver may be added up to about 20%.Cadmium, zinc, thallium, bismuth and lead may be added up to 15% each,added to the charge in melting. The lower eflective limit for the alphapromoters is about 0.5% and preferably about 1%.

The elements Ce, Be, As, S, Te and P are strictly compound-formingelements. They do not have appreciable solubilities in either the alphaor beta phases, but form intermetallic compounds with titanium. The betapromoters silicon and beryllium are likewise best grouped ascompound-forming elements, in view of their above-mentioned lowsolubilities in titanium and the tendency of the beta phase stabilizedby these elements to decompose rapidly into eutectoid products. The Ti-Sn alloys of the invention will tolerate only relatively small amountsof these compound-forming elements, i.e., up to a total of about 2 or 3%maximum, the lower effective limit being about 0.1 or 0.2%.

Substantially pure and ductile metallic titanium may be produced atconsiderable expense by the so-called iodide process described in U.S.Patent 1,671,213 to Van Arkel; while ductile titanium of commercialpurity is produced more cheaply by the magnesium reduction of titaniumtetrachloride by the process described in U.S. Patent 2,205,854 toKroll. Both procedures, particularly the latter, result in somecontamination of the titanium metal with one or more of theinterstitials, carbon, oxygen and nitrogen. But since, as noted above,these are all alpha-promoting orstabilizing elements, the resultantsomewhat contaminated titanium metal obtained, has at room temperaturesa single phase, all-alpha microstructure.

The all-alpha, all-beta and mixed alpha-beta alloys of titanium havetheir respective advantages and disadvantages. Generally speaking, thealpha alloys provide good all-around performance, having goodweldability, and being strong and resistant to oxidation, both cold andhot, but are somewhat inferior as to ductility. The all-beta alloys, onthe other hand, have excellent benedability and ductility, are strongboth hot and cold, but are somewhat vulnerable to atmosphericcontamination, particularly at elevated temperatures. The mixedalpha-beta alloys provide a compromise performance as between all-alphaand all-beta alloys, being strong when cold and warm, but weak hot,while possessing good bendability and ductility, with a moderate degreeof resistance to atmospheric contamination.

Since the TiSn base alloys have, as above noted, an all-alphamicrostructure, they may be readily welded in tin contents up to about16%, with no appreciable impairment of ductility in the welded ascompared to the non-welded portions. They also form an excellent basealloy for the ternary and higher component alloys of the invention, thatmay be also welded without appreciable loss of ductility in the weldedas compared to the non-welded portions. This is particularly true asregards the above-mentioned alpha-promoter additions to the base alloy.Also, in general, the ternary and higher component alloys made byadditions of the beta-isomorphous elements above designated are weldablewithout appreciable impairment of ductility. It may furthermore bestated that in general the alpha-beta alloys according to the inventioncan be produced to have ductile welded portions if suitable post-weldingheat treatments are applied as described in the co-pending applicationof laffee et al., Serial No. 585,177, filed May 16, 1956, which is acontinuation-in-part of application Serial No. 305,- 504, filed August20, 1952 and now abandoned.

Tin is soluble in alpha titanium to the extent of at least 15%, andalloys of titanium with up to 15% tin are all in the alpha phase. As thetin content is increased, the beta transformation temperature rises, andat a tem- 19%, a peritectoid reaction occurs. In alloys containing about20 to 23% tin, two intermediate phases formed at ,difierenttemperatureshave been tentatively iden The following Table I gives, for comparativepurposes with the further test data presented hereinafter, test resultsshowing the improvement in mechanical properties, resulting fromadditions of tin over the range of about 1 to 23%, to both iodide andcommercial purity 15 titanium base metal, with and without furthercontrolled additions of one or more of the interstitials, carbon,

m 0 w f O t m n O c m a d m 0 0 n m m m o H a m f d O e m m m 4 m n w wM a a 5 m n a u a mmmaam w wu .PM O m tm cu om mmmrmm W323 a v O Mm mvmm m V M Pm a imm mum Wm H A, mamw w m emma pmtm m m m p mm m .m .m a.n. d m mmmm mmmmmw ue mm mwmawm Min. Bend T wunnmnw wnwmmamum mmmmmwmmaw Percent Rednc- Vickers tion in Hard- Percent Elonga- TABLE IUltimate tion in 1" Area Ti-Sn binary alloys [Annealed condition]Tensile Properties: p.s.t. 1,000

571 856 77 79 m%m4wm%mmfln3aufiwslfio w nfl%33fln mfi3w 2122333333343433 "9033333333 E S A 6 0 3018325 957265 1 765 12837 6 V 1485991 1 E U S n I A m 1 9 1 1 11 1 05767 8216199684 9986 B mnmmmmimwznuuunnn winmmmmmm T zznnimi 22 a 1 ziiim i I m T m. m n u m m nmn nmmmmmmwmnmm umnm m imnimmmmnnmh mnmiwin... t B T P E L mm m m 7 6 7 9m 4 07s 7 58755 9 7 9 91 74 00 86 1 11839 319 69214 9 e 5 311 m Mm w nm mm mmfi nmn m u mn m mnn nmmnminmmiim mom I E 1917 M 8 3 8 4 N 221212 M 2n 11 1 a 0000000 0 00 0 o 0 0 O 0 0 0 0 Q0 0 0 u 0 0 00 u 0 0 7 6 8 0 0 U o10 0 nw 0 0 0 000 O 0 Composition, Percent (Balance Titanium) D 5 v mwmmmmmmmmmmmmwm Z From these results it will be observed that additionsoftin up to about 23% greatly strengthens the metal while retainingadequate ductility for fabrication pur-. For the iodide tita-.

poses, i.e., forging, rolling, etc. nium base the yield strength is morethan quadrupled from 27,000 to 135,000 p.s.i., while the ultimatestrength is more than tripled from 43,000 to 149,000 p.s.i. For anygiventin content further strengthening results from controlled additionsof one or more of the interstitialsone or more of the alpha promoters,beta promoters, or 20 compound formers above discussed the followingTable II gives test results for additions of one of the more importantbeta promoters, namely, manganese:

of ductilitys l n fact, for. additions of manganese up to about 6%, theductilityisactually-increased as compared to the alloy omittingmanganese, while at the same time, increasing the ultimate strength upto about 150,000 p.s.i. The effect of interstital ,additions to themanganese-containing alloy againenhances the strength without seriouseffect on ductility as shown by comparison of the 9% tin, 2.5% and Mnanalyses.

The following Tables HI and IV show the effects of molybdenum additionsto the titanium-tin base alloy. In Table III all alloys are in theannealed condition; whereas Table IV gives the properties of the alloysin various heat treated conditions. Here again, as in the case ofmanganese, the molybdenum additions greatly increase the strength of thealloy while retaining adequate ductility. For example, with the 10% tinanalysis and a 7.5% molybdenum addition, the ultimate strength isincreased from 110,000 to 140,000 p.s.i. with no loss in ductility, asshown by comparison with Table I. At the tin level the ultimate strengthis increased from 123,000 to 167,000 p.s.i. with no loss in ductilityupon the addition of 5% molybdenum. The effect of adding interstitialsTABLE II T1Sn-Mn alloys (commercial titanium base) [Annealed condition]Composition, Percent (Balance Tensile Properties:

Titanium) p.s.i. 1,000 Percent Elongation i 1!! Sn Mn 0 0 N 0.2% OfisetUltimate Yield Strength Percent 'Reduction Vickers Min.

in Area Hardness Bend T 50 276 1. 7 48 261 1. 6 49 273 1. 7 55 369 1. 545 364 1. 6 46 344 1. 5 46" 336 1. 2 39 369 1. 8 39 389 1. 8 46 397 2.890 353 1. 7 37 424 4. 7 36 421 4. 8 38 426 2. 3 11 350 1. 6 r 36 296 1.5 44 341 1. 6 48 326 1.7 51 356 1.4 39 363 1. 6 25 375 1. 4 38 369 1. 435 385 1.2 27 386 2. 9 29 377 3. 7 B1" 404 Br 49 316 0. 8 41 324 1. 6 15481 7. 0

Comparing the results of the above table with those 70 is shown bycomparison of the values for the 9% tin,

given in Table I, it will be seen, for example, that for the 10% tinalloy containing no manganese, the ultimate creases ranging up to about160,000 p.s.i. with additions-of 2.5% molybdenum analysis wherein theultimate strength is increased from 113,000 to the order of 130,000 to140,000 p.s.i. with no appreciable effect on ductility. The same orderof increase occurs at the 9% tin, 5% molybmanganese up to about 9%,without serious impairment 7 denum level.

iron analyses:

TABLE VI TiSn-Fe alloys [Annealedtconditiom] previous data, the additionof the interstitials enhances be seen by comparison of the 9% tin, 0.5%

" and a titanium base of commercial purity, the addition of 2% ironincreasesjthefultimate strength from 123,000 to 177,000 p.s.i.withsubstantially no change in ductility. At the 10%11'1'1 1evel,*theultimate strength is increased 5 from 110,000 to 150,000 p.s.i. with nochange in ductility the strength properties with no loss in ductility ascan 45 upon the addition of 4% iron. Here again; as in the TABLE VTi-Sn-Cr alloys [Annealed condition] Other .T mi 641 MM 11?]. 0 1LLLLQQLnLLQL LLLLLZZOmLZLZZ B s s r t r r 7 i e 5199108118903858616199810866352 S 6 2 712 35 38546678658956 H tw 7 m mmmm195 E 5352637 1689 4 268 0 5 74 5 e n A t P .1 E B s A m n B m 1 207 7891 mmmm M 11 I w BMWMHHMHMHNH HH$WM 21BB12 PE w m N T e I 1 23 41 0 6061915 m 4422 mm mm m m u umm mmmunnnmmmmmwnmmmnimii1 D. I. T. 01 Us E 0mm D R 81 t I E H! an D 857 24201 72 3 1 1 15 4445326896 0 1 l 300 mp mm 1 m mun u mnmnmummmmuumnmhri T 0 O It will be noted byv comparisonwith Table V below shows the eifcct of chromium additions to thetitanium-tin base. The observed improvement is of the same general orderof magnitude as for the Composition, Percent (Balance Titanium)molybdenum addition and hence requires no detailed comment.

Q 00 233:5"5. .LIYIQQQQQQQQQQQQ 55 5 5 5 4 4mfl .0 1 2 5m24.68m4L0QQLZQ0L20Q 506 r 5 9 9999999 Table VI shoyvs the effect ofadding iron to the titanium-tin base.

Table I that the iron addition tremendously..incr eases the ultimatestrength accompanied in general by retention of adequate ductility. Withthe 15% tin analysis .T E 7 If .1 090 3065763 Mm 1L3 LaaaaLL .B ne it We t e k- 733 5 84 952 m 7 nan amamawa t a r n 6 r I Cunt t t t 3% "mm mewaowrsw PR .m t t E M s t A M fiw. B V U Y t mmm M w m mumwmmm PE m A tT wk I u e n T T mm mm 1 wmm L manwtwnnmm 6 T 11 A 111 1111 m ms E 0 mx7 n R 9 1 t T. E H5 em D m 2mm 0 men M nwmnm n 0 1 1 M 1 1 n n O C m m un u n u n u n n u n n wm m u n n u n n n n n n m P m 6 no 5 T r 555 13fl 2 2 2 262001257 new m m n 5 05 145999999 0B c( s 11 t TABLEVI--Cont1nued m osition, Percent Tensile Propertieli' (B 00 Titanium)p.s.i. 1,000 Percent Percent Elonga- Reduc- Vieker Min.

tion tion Hard- Bend T 0.2% Ultimate in 1" in Area ness 8n Fe OtherOfiset Strength Yield COMMERCIAL TITANIUM BASE-Continued 10 1.5 108 12018 40 330 1.8 10 2 121 132 9- 31 347 1.5 10 3 133 147 14 36 359 2. 0 104 137 150 10 87 370 1. 5 5 185 190 5 16 446 B1 10 7.5 176 179 Y 8 31 4266.1 2 170 177 12 32 411 2. 3 9 0. 25 0.250 113 119 25 54 343 2. 5 9 0.25 0. 20 106 122 21 38 341 2. 3 9 0. 0. IN 109 21 36 304 2. 3 9 0. 5 0.250 104 125 24 50 338 1. 3 9 0.5 0.20 105 125 16 321 1.8 9 0. 5 0. IN 91105 17 42 306 2. 4 9 1. 25 0. 2C 123 134 17 27 362 1. 7 9 1.25 0.20 110123 17 42 383 1.9 9 1. 25 0. 2N 126 142 16 45 380 1. 7 9 2. 5 0. 20 143152 18 396 1. 5 9 2. 5 0. 20 139 152 15 41 408 2. 3 9 2.5 0.2N 153 16415 34 404 B1 Table VII below shows the efleets of additions of the Icopper, zirconium, cobalt, and nickel to the titanium-tin 7 betastabilizers vanadium, tungsten, columbium, tantalum, base.

TABLE "II Ti-Sn base plus V W, Cb, Ta, Cu, Zr, Co, Ni. Si; Be alloys[Annealed condition unless otherwise indlcated.]

Tensile Properties: MBR,T. Omfiposition, Percent p.s.i. 1,000 PercentPercent -V1ekers (B anee Titanium) Elongation Reduction Hardness 0.2%Oflset Ultimate in L T Yield Strength IODIDE TITANIUM BASE 10Sn2.5V.- 7897 10 16 0. 5 84 106 7 36 0.6 54 76 10 47 1.1 68 81 12 53 1.7 72 19 323.1 75 94 15 29 2.0 112 9 29 2.9 98 108 22 38 1.9 3 94 108 14 37 3.4 114128 11 28 6.3 94 20 40 2.2 106 117 18 43 2.1 99 113 18 42 3.7 129 136 1539 3.3 123 138 1 9 5.7 98 121 2 14 2.0

OMMERCIAL PURITY TITANIUM BASE Vlckers Hardness u 089622622r-1 0 uo-larszozrsrrr r u n 38068478 m aeaeaaeei no oe L eeoe a B 00 oeoiieslea n n n u n n R u n n u u u m u n u n u u m 8o7786666rr00 06r241876775r1 90 13 02523435 12 12422azo LzoLooo LLzLLaLaL eLLoooooaoLLzL L v 990 u B 1 22 oLnLLzzz L2 5 5 LL25 1 T n .u R u B 88 mm m m M L222 5457 59925 9 88012 m zone 2235 .m m i v n Percent in AreaPercent in Area Percent Elongation Reduction 841 12745 g 1 7 1 111w11111m1m1mum 1mn m nm m m mnmm uw m Percent Elongation Reduction Hardnc inl1113L04440l491380L33989-1 1.11 1112122111 111 21111 Strength TABLE VIII[Annealed condition] p.s.i. X 1,000

Strength Tensile properties:

0.2% 7 Ultimate Offset Yield TABLE VIIContinued Tensile Properties:p.s.i.Xl,000

Yield 0.2% Ofiset Ultimate Mechanical properties of Ti-Sn basealpha-beta alloys containing two beta stabilizers (commercial puritytitanium base) Composition, Percent (Balance Titanium) COMMERCIAL PURITYTITANIUM BASEContinued l 1,600 F. quenched. I 8 hrs. at 1,400 F. I 16hrs. at 1,4o0 F.

Table VIII below shows the efl'ects of adding a mul plicity of betapromoters to the titanium-tin base.

Composition, Percent (Balance Titanium) 1 r186d6r0 r0090456958 6 m75730022706211 5097281 Idle r4650 r r r666 28 2 A" L lulu; Bend RadiusVickm A 1 wmwwmmmmmmammmmwwwmmwmammmmmmmwwmmmmManamaaammmmmmwmmmmmmmmwmmmmmWm Percent Reduction Hardnessin Area ma mmamma aa mewemnmaa aaneooeaawanwoundnenwmnmw mmuwwnwmeunuauamnmama Percent Elongation i 1!! m h M H t w e832906432208135571721924.61345G5 0 e t 1 1111.....1 1111 11 11111111miunumunmmmmmumrmmr w mmmwm mm mmnnmumw strengths, acceptabletensile ductil 7 Ultlmate Strength TABLE VIIIContinued Tensileproperties: p.s.1. X 1,000

0.2% Ofiset Yield Composition, percent (Balance Titanium) 1 The tensilestrength was reached before the 0.2% ofiset yield strength,

1 Detective sample.

From the test results of Tables II to VIII, inc., the following generalconclusions may be drawn with respect I dn ma w Ph. X ma h m m eam mwmwd u 1 ductilities, poor thermal stability, to the eflfect of single andmultiple beta stabilizer addiof the TiSn-5W alloy are in tions to thetitanium-tin base. The beta isomorphous welded, except for extremely lowadditi elements V, Cb, Ta, Mo and Zr alone or in combination ments. Onthe other hand, by judicious selection and with each other, producealloys having similar propcombination of the beta promoters from one ofthe erties. These alloys have medium strengths, good duca groups abovementioned with those of the other groups, tility, good thermal stabilityand, as shown below, are multiple beta stabilizer alloys may be producedwhich generally ductile as welded. The elements Fe, Cr and combine thegood qualities imparted by the elements Mn which form systems containingsluggish eutectoid from the groups selected, while tending to suppressand reactions, produce alloys which have high strengths, good minimizetheir undesirable qualities. Thus, for example, ductility, fair thermalstability and are generally brittle as the combination of betaisomorphous elements with the welded, except for low alloy contents ofsuch additions; sluggish eutectoid elements results in alloys that haveThe elements with rapidly transforming eutectoids, Co, improved thermalstabihty and weld ductility as com- Ni, Cu and W, produce alloys whichhave medium pared'to those made with the sluggish eutectoid elementsTABLE IX [Annealed condition.]

Thus it will be seen by a comparison of Tables I and properties ofadditions of the alpha stabilizer antimony to the titanium tinbase,withand'withoutadditions 'of therinterstitia ls carbon, oxygen andnitrogen:

Ti-Sn base plils Sb alloys d mT 235779 ou 32 ULnMLrZ LK ZLLZZBZZLLZABZQwZ-m N V 9 1 245328 368 H %MM%%6M filwflmflm902344m343 V 2 2333323233322 333333 3 t n w GOT 195674 64 000337978 00066 MMA $535333fifl441 444343 342 G P m t R E s m A t mau B V. 3 272 818776 90 m2m211MM NMUH 121111 MW 8 i a a PM E m E S N A A mm B m g M e n 7860575 T 67415684160348524 11353 m mm m ummm n nmm mnmn11111 wm Us N T R t a m n TU us at I n SD Nuwm T 2247317 P 69406 190745 985 n n 6 e 12 .024 P o m mm m M m mu m mll 111 n m I I 0 D C t 2 R N I 0 E M 8 m m u a I o "I B I1I I" I r\ n) .6, m m a "I n :1 a ,t 1 M 5 0 1 tw nties 1 T a. .7 n w ,"1;1l1 wmmm ma n mios p m 55 5 5 5 2 5-07 a mmmmmm 19 alone. On the otherhand, the test data shows that combinations of beta isomorphous elements"with the rapid eutectoid elements do iiot ult in improved thermal 40 IXthat antimony has about the same strengtheningefiect as an equivalentweight of tin and may be substituted therefor without undueembrittlement within the range of proportions set forth in theabove'table incolumn 20.

The following Table X shows-the effect on mechanical properties ofadditions of the alpha stabilizers bismuth, indium, cadmium, silver,thallium, lead and zinc to the titanium-tin base .Min.

Percent TABLEX [Annealed condition .1

"cal

Ti-Sn base plus 'In, Bi, Pb, Ag,Cd, T1 and Zn alloys TitaniumComposition, Percent (Balance Co and Ni.

The following ,TablegIX: shows the eflfeet :on mech mOLLZZLDMLZZDMZLLZZZAAML T B 55012486672U81181268 6 V 2 4 2283 wlwN%NZMWHM%% MZNM%3332 8 n r 17 0015134644396 557 m 83%445444544 434M445 9m 4 r E 8 216 m s mwwmmmmwmwmlmzimmmw m A m a B 0 M I E U v t I 3 6676388891183459 mh N 4%6wm000280017770003fi n A 1111 111 .1111. mm m H..T U E l D I 6 34 13953912330 t W5: u%%09fl%09055590936 qe 1 1 1 1 1 12mm 0 Q Y I O CON 00 ooN m 34 l o mfimd 11.11.11 I Sggggg L ZmJCAAA Ammmmmm 22 221 11m1m2 O 000 000 0 mwmwmlm lll mmll l S TABLE X-ContmuedComposition, I 7 Percent (Balance g f gfi I Percent itamum) Percent..Reduo- Viekers Min. e Elongation tion in Hard- Bend Sn Other, 0.2%Ultimate iin 1" vArea ness '1 a Oflset Strength V Yield 1 COMMERCIAL.PURITYTITANIUM BABE 49 70 24 44 197 1.3 6 71 90 '14 v 42 246 1.5. 10 1B182 97 i 48 297 1.5 10 2.631 86 99 -17 297 .2.

0 2.531 74 24 49 206 1.1 10 1111 79 94 25 61 283 1.7 10 2.5In 88 101 2148 297 1.6 ,10 61in 92 104 17 49 289 1.9 10 10111 102 111 20 '45 325 42.7 v 10 1006. 79 92 18 41 270 1.8 I 10 lAg "80 96 17 48 252 1. 7 102.5Ag 82 95 18 47 287 1.5 10 fiAg 87 102 19 51 809 1. 7 10 10Ag 91 10418 45 309 2.5 10 10Pb ,87 101 23 47 314 2. 8 10 10211 73 86 22 62 2681.6

* Considerable weight loss occurred during melting.

Table XI below shows the efiects of additions of the various compoundformers'to the titanium-tin base:

. IABLE x1 Alloys 0 Ti--Sn base plus compound formers Si, Be,- Ce, B,Te, etc.

tendency to become embrittledas a result of welding. As

further shown in said application, beta-containing alloys -'[Annealedcondition] Composition, Tensile Properties: Percent (Balance psi.Xi,000

Titanium) Percent Percent Vicirers Min.

Elonza- Reduction Hardness Bend T tion in 1" in Area Sn Other 0.2% 011-Ultimate 1 i set Yield Strength IODIDE TITANIUM BABE 10' 85 99 20 36 2981.5 '10 10c 67 76 16 B4 250 2.0 10 We 61 78 17 48 232 2.7 10 Y 2.5Te 7288 7 20. 242 1.1 10 0.513 54 72 21 38 236 1.8 10 2.5T]: 22 67 238 1.9 10mi 97 16 38 305 1.6 10 0.2Be 70 90 12 22 273 1.6

COMMERCIAL PURITYTITAN IUM BABE 10 91. 110 11 i 30 296 1.6 10 10a 80 .9417 39 285 2.4 .10 2.500 75 92 y .15 a 33 276 3.2 10 0.581 I 17 45 3251.5 10 151 97 109 17 35 330 5. 0 10 281 104 a 108 3 v 8 383 7.0

"Considerable weight loss occurred during melting.

The welding characteristics of the various types of alloys of thepresent invention, are described, and the weldable alloys thereof,coveredby. the above-mentioned co-pending joint application of theapplicantsJafiee and Ogden herein, 'Serial No. 585,177. As thereinshown,

the all-alpha or substantially all-alpha titanium-tin base alloys of thepresent invention, containing up to about 16% tin, are weldable' withoutserious impairmentfiof ductilities, substantially throughout the entirerange of analyses that such alloys are ductile in the cast or wroughtcondition. The same'is shown in said application to be generally truewith respect to the beta or mixed alphabeta titanium-tin alloys obtainedby additions of betapromotersof thebeta-isomorphous group, i.e., Mo, V,Ob, Ta and Zr, although certain of the molybdenum-conformed by additionsof the sluggishly eutectoid beta promoters, Cr, Mn and Fe, are generallyproductive of brittle welds when present insubstantial amounts, i.e.,about 23%, although certain of the higher alloy analyses restricted toCr and/ or Mn additions are ductile as welded or can have theirductilities restored by post welding heat treatment as above mentioned,i.e., those containing up to about 7-8% Mn or up to about.l8% Cr. Thebeta alloys formed by additions of Co, Ni, Cu and W having rapidlytransforming eutectoids are intrinsically brittle in the weldedcondition when these additions are present in excess of about 2 to 3%,Le, their ductilities cannot be restored by post welding 'heattreatment. The compound formers likewise impart intrinsic brittleness aswelded to the titanium-tin base alloy when present in amounts exceedingabout 2 to 3%.

Our investigations have e'stablished'thatthe alloys in accordance withthe invention containing about 10 to 15% tin are wholly contaminationresistant attemperatures up to 1050 C. and probably higher regardless ofthe type of alloy, i.e., whether all-alpha, mixedalphabeta or all-beta.They have further established thaflthere is a marked or criticalreduction in contamination resistance commencing at about tin ascompared to that of the same alloy containing no tin. Themtin additionproduces free scaling alloys in most cases, but this tendency to freescaling appears to be reduced when large quantities of beta stabilizersare present. p

The findings above stated are based on the .test results set forth inthe following Table XII, the data for which was obtained by are melting15-grambuttons of each of the compositions indicated in thetable,;including the tin-free alloy bases. The buttons were "f orged at850 C. to about square x 1% long. forged billet was then descaled andsectioned into two. samples. One sample was heated in air for four hoursfat 1050 C. and furnace cooled. The second sample rec;e'ived the sametreatment in argon. These samples were furnace men, with resillts asrecorded in the'tablef TABLE XII Oxidation test data for Ti-Sn basealloys containing Ta, W, Cb, W, Mo, Fe, Cr or Mn [Oonditionz 4 hr. at1050 C. in air and furnace cooled] Metal- Depth of 1 IncreaseComposition, percent Weight Thiclmess Oontamiin VHN (Balance Titanium)Gain Loss, nation, f oMils gJdm. Mils Mfls Below Surface 3.5 60 240 15.5 18 40 13. 5 19 Nil Nil 11. 9 18 N 11 "Nil 2.00 Nil 80 350 6.49 Nil 55200 16.09 21 30 3 60 19.41 28 Nil Nil 3. 52 1 80 220 23.80 36 40 i 6020. 60 29 30 30 12.27 11 N11 Nil 1.66 Nil 70 230 5.19 N11 40 150 14.8020 Nil Nil 18.67 26 Nil Nil 5. 18 2 85 300 12.38 15 35 50 14.88 18 NilNil 18. 70 35 Nil Nil 2.8 2 so 280 5.0 22 40 I 50 20.9 32 10 50 20.9 3020 40 3.8 4 20 '80 12. 7 21 15 50 12.4 22 Nil Nil 15.5 21 20 60 3.8 3120 280 112.0 7 16 T 25 80 10.7 18 M50 8.5 14 N11 20 3.7 2 80 250 6. 6 a9 9.4 14 'N11 Nil 7. 5 1 6 -Nil J 90 4.6 0.5 q 280 9;9 7 6. 6 10 Nil Nil12.8 24 Nil Nil 3.5 0.5 40 300 3.6 0.5 Nil Nil 4.8 A 8 .Nil Nil 3. 1 6Nil Nil 3.0 2 80 300 .12. 1 18 5 100 '14. 9 '21 'Ni1 20 12.8 20 Nil Nil3. 7 2 so .250 6. 6 3 9 40 50 9.4 14 N11 Nil 7. a 6 ,Nil a N11 As above.stated thegrnajority of the specimens were found to.befree scaling, butthe -Ti (5-15)Sn-10Cr alloyshad rather adherent sealeswith little lossin metal 5 orridation and no noticeablecontamination as measured byhardness. The Ti .10(;r control alloy had a similar scale, but; theunderlying rnetal was highly contaminated. --Thus, when-10% chromium-ispresent,-tin appears to m iaiiai ljt iaat aiet .raiateaa yithqu the reing. characteristics, thus indicating utility of these alloys atelevated temperatures.

Q ur investigations have f urther shown that the Ti (5-1-;5)n10Cr alloy,with and withoutadditions of.-,up to of onepr moreof iron, molybdenumand manganese have expellent eleyated temperature hardnesses combinedwith contaminationresistance at temperaturesashigh as- 800 to 900 F.,and good hardness at :temperatures up to 1100 to, 1200; F. is: shown bylthe test results submittedin the following Table XIII.

Hot hardness values of Ti-Sn base alloys for elevated 30 .temperatureservice n hotrolledandann ealed] Composition, v ,250 v 1500 760 10001.250 1,500 80 gereengtfiglialnnca 80]. ,F. F. F. iii, F. F. F. .2 H. .735

195 rd 116 72 as 233 221 ms 133 107 so 23 287 235 189 "1152 "132 11 27292 276 223 123 .32 18 476 235 269 241 '160 "51 27 351 294 261 235 14442 24 359 e13 275 254 -55 26 was 327 1219 ;265 179 as 32 317 5Sn10Cr5Fe353 322 315 244 92 37 409 ""6Sn 100r5M0' ans --290 246 "240 -75 333 '34s5Sn--10Cr -5Mn- 324 314 .286 271 186 as 31 376 Mn e77 340 2 69 235 1064a Hardness at room temperature after being heated to 1,500 F. tztmefled2 hours at 85010. prior to testing; other analypes annealed a z-Referringto-the above-data, a comparison of the hardne ss values of thebinary Ti4n alloys with the binary Ti Cr.alloys shows that it thefchromium or beta addition which promotes the higher hardness at.temperatures up to 800 to 900 F. As further shown by the above data,;,the.combination of tin and .chromium provides an added hardeningincrement, due to the tin, h. .n im ne at eyate u te p am e As ..ther.shown, the.substitutionofimanganese, iron and molybdenum for part of thechromium-has varied efiects. LIron additions resultjn. higherhardnesses, Zwhich pre- ---.va temperam nt? wt 2 M n ne .-.ditions do.not. change the. hardness. ofthe -TiSn-Cr alloy, while molybdenumadditions produce some -decrease hardness which prevails at alltemperatures re- I ferredto- On the basis ofhardness alone, the Ti.5Sn-1 0Cr 5 Fe alloy is best. However, onthe ,basislof strong .and ductile.room temperature properties as well as eler te t e a u .sent afiaafi nre i a and hardness, theTi Sn- Cr Q/Io, Mn) alloys are of bestall-around utility.

The room temperature properties of these alloys are given in thefollowing Table XIV:

TABLE XIV 26 ultimate strengths at least 30 to 50% in excess of theunalloyed titanium base Mechanical properties of TiSn-Cr base alloys forelevated temperature service [These alloys were 980 0. forged, hotrolled at 1,400 F. to 0.080 inch, descaled, hot rolled at 1,300 F. to0.040 inch, held minutes at 1,300 F., furnace cooled at 1,100 E, and

air cooled to room temperature] The alloys of the invention may be made:by melt casting in a cold mold, employing an electric arc in an inertatmosphere, or may be produced in other ways in which the alloy isrendered molten before casting.

Where the alloys are to be used in the form of sheets, the minimum bendductilities may range as high as T, and where they are to be used inmassive form, as in forgings, the percent tensile elongation may rangeas low as l or 2%. Minimum bend ductility T is defined as the minimumradius to which a specimen can be bent through an angle of 75 withoutfracture, expressed as a multiple of the specimen thickness.

It will be observed from the data in the tables above set forth that thealloys of the invention have ultimate tensile strengths at least 10% inexcess of the unalloyed titanium base metal, and in the vast majority ofinstances,

References Cited in the file of this patent UNITED STATES PATENTS2,779,677 Jafiee et a1. Jan. 29, 1957

